K65R-associated virologic failure in HIV-infected patients receiving tenofovir-containing triple nucleoside/nucleotide reverse transcriptase inhibitor regimens.

High rates of early virologic failure associated with the emergence of the K65R mutation in HIV-1 reverse transcriptase (RT) have been reported among HIV-infected patients who received novel, tenofovir-containing, triple-nucleoside/nucleotide reverse transcriptase inhibitor (NRTI/NtRTI) regimens as their initial therapy. This review surveys the findings of prospective and retrospective studies in this regard, examines the significance of the K65R mutation and other factors associated with reports of early virologic failure among patients receiving tenofovir-containing NRTI/NtRTI regimens, and discusses clinical approaches to preventing and managing HIV drug resistance and treatment failure associated with the K65R mutation.